Re: [PATCH v5 4/5] KVM: selftests: arm64: Skip all 32 bit IDs when set_id_regs is aarch64 only

On Tue, 17 Mar 2026 20:10:37 +0000,
Mark Brown [off-list ref] wrote:

On an aarch64 only system the 32 bit ID registers have UNDEFINED values.
As a result set_id_regs skips tests for setting fields in these registers
when testing an aarch64 only guest. This has the side effect of meaning
that we don't record an expected value for these registers, meaning that
when the subsequent tests for values being visible in guests and preserved
over reset check the value they can spuriously fail. This can be seen by
running on an emulated system with both NV and 32 bit enabled, NV will
result in the guests created by the test program being 64 bit only but
the 32 bit ID registers will have values.

I don't think papering over this problem is the right thing to do.

If the issue is that you have HW that has both NV and AArch32, then
KVM needs to be fixed to make the 32bit IDregs RAZ when NV is present
because that's not a configuration we support.

	M.

-- 
Without deviation from the norm, progress is not possible.